Propagator Calculations on Molecular Ionization and Excitation Processes, Ortiz Joseph

Renormalizations, which sum classes of diagrams to all orders in perturbation theory, are applied to the electron propagator. The separation of relaxation and correlation self-energy diagrams enables the construction of electron propagators that include relaxation contributions to all orders. Correlation self-energies are obtained in second order, third order, and in the diagonal 2p-h Tamm-Dancoff approximation, which is also a renormalization. These propagators are applied to the electron binding energies of CN, NFL, PFL and Cl2. An alternative propagator renormalization through the transition operator method reference state is applied to the electron binding energies of Ne, FLO, Ne, H2O, NH2, and CN.

The anti symmetrized geminal power wavefunction, which is the form of the consistent ground state of the random phase approximation of the polarization propagator, is variationally optimized for the LiH groundstate potential curve. Random phase approximation polarization propagator calculations yield excitation energies.

Physical concepts suggested by these theories are discussed.